Electron discharge device



Jan. 9, 1940. A. L. SAMUEL ELECTRON DISCHARGE DEVICE Filed July 22, 1957F/c. 2 l,

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ELECTRON DISCHARGEA DEVICE y Arthur L. Samuel, Summit, N. J., assignorto Bell Telephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application July 22,

10 Claims.

This invention relates to electron discharge devices and moreparticularly to such devices, for example of the general constructiondisclosed in my Patent 2,063,341 granted December 8, 1936J especiallysuitable for the generation and ampliiication of ultra-high frequencyimpulses.

In electron discharge devices adapted for the generation andtranslation'of ultra-high frequency currents, for example currents offrequencies corresponding to wave lengths of one meter or less, thevarious electrodes, such as the cathode, control grid and anode, usuallyare spaced very closely inv^` order that very short transit times may beobtained, and the control grid, therefore, is of small dimensions.Consequently, during the outgassing treatment of the electrodes and theoperation of the device, the control grid may become heated to undulyhigh temperatures. As a result, undesirable secondary emission from thegrid Amay occur or the grid may be destroyed.

One object of this invention, therefore, is to prevent deleteriousheating of electrodes in electron discharge devices so that the deviceswill be capable of handling safely relatively highv power.

Another object of this invention is to expedite the fabrication andassembly of electron discharge devices.

In one illustrative embodiment of this invention, an electron dischargedevice comprises an enclosing vessel including a vitreous portion and ametallic portion constituting the anode of the device, a cathode, and acontrol electrode assem- 35 bly. The control electrode assembly mayinclude a grid between the cathode and the anode and a metallic tuningmember forming an inductance and a capacitance of predeterminedmagnitude with the anode.

In accordance with one feature of this invention, the control electrodestructure is provided with a relatively large surface metallic portionexposed or thermally coupled to the atmosphere whereby the heatdissipation from the control electrode assembly is increased and thegrid thereby maintained at a safe temperature during the Voutgassingtreatment of the electrodes and the operation of the device.

In accordance with another feature of this invention, the cathode andthe control electrode structure are fabricated as a unitary assemblywhich may be inserted as a unit into the enclosing vessel and mountedtherein! The invention and the foregoing and other features thereof willbe understood more clearly and.

1937, serial No. 155,018

fully from the following detailed description with reference to theaccompanying drawing, in which:

Fig. 1 is an elevational view in perspective of an electron dischargedevice illustrative of one embodiment of this invention, portions of thedevice being broken away to show details of construction more clearly; y

Fig. 2 is an elevational View mainly in crosssection of an electrondischarge device illustrative of another embodiment of this invention;

Fig. 3 is a fragmentary view in cross-section showing a modification ofthe embodiment of the invention illustrated in Fig. 2; and

Fig. 4 is a fragmentary view in cross-section of a modification of thestructure illustrated in Fig. 3.

Referring now to the drawing, the electron discharge device shown inFig. 1 comprises an evacuated enclosing vessel having a vitreous portionI and a cup-shaped metallic portion Il hermetically sealed to thevitreous portion Il) and provided with an external annular flange I2 bymeans of which the device may be supported. Mounted upon and secured tothe metallic portion II is an anode element having an extendedcylindrical portion I3 and a generally annular portion I4 provided withdiametrically opposite, parallel U-shaped recesses I5. The annularportion I4 of the anode element abuts a shoulder I6 in the inner wall ofthe metallic portion II and may be affixedv to this portion as by solderIl contained initially in an annular groove in the outer wall of theannular portion I4.

A control electrode structure is cooperatively associated with the anodeand includes a metallic cylinder or sleeve l'coaxial with the annularportion I4 and provided at its inner end with diametrically' oppositeslots in which a metallic plate I9 is fitted. The metallic plate may belocked in vposition by a plurality of cross members or wires 2|extending therethrough and through the cylinder I8, and carries a pairof grids 22, each disposed inone of the channels or grooves I5 andpreferably coaxial therewith. Each of the grids may be composedv of aplurality of parallel U- shaped wires having their ends alxed, as bywelding, to opposite faces of the plate I9 and further held in positionby backing wires 23 also aiiixed, as by welding, to the plate I9. Themel tallic cylinder I8 is provided at its outer end with a. flaredportion 24 hermetically sealed to a vitreous dished member 25, and isencompassed by a cylindrical metallic member 26 coaxial with andadjacent the cylindrical portion I3 of the anode member. The cylindricalmember 26 is provided with a. flaring end 21 sealed hermetically to thevitreous portion I8 and is joined to the cylinder I8 by a metallic disc28, rigidly aiiixed to both the cylinders I8 and 26, as by welding.

As described in my Patent 2,063,341 aforementioned, the members I8, 26and 21 may be so dimensioned and disposed that they constitute aninductance with the anode, the inductance being of such magnitude, forexample, as to form with the interelectrode capacitances a circuitresonant to the frequency at which the device is intended to operate.The cylindrical members I8 and 26 may be spaced to dene a blockingcondenser of desired magnitude. A-suitable potential may be impressedupon-the control grids through a leading-in conductor 28.

As will be seen, the disc 28 and the members 24 and 21 arel exposed tothe atmosphere and provide relatively large area heat radiatingsurfaces. Consequently, heat generated in the control electrodestructure during operation of the device, and which might be retainedbecause of the mass of this structure and particularly of the tuningmember 26, 28, will be dissipated rapidly so that this structure will bemaintained at a relatively low and safe temperature and secondaryemission from the grids 22 will not occur. The rate of heat dissipationmay be further increased, if desired, by circulating a cooling medium,such as a stream of air, over the outer surfacesof the disc 28 and theend portions 24 and 21 so that the power capacity of the device may beincreased accordingly.

Disposed within each of the grids 22 is a cathode 38, which may be alinear thoriated tungsten filament coaxial with the corresponding grid.

'I'he cathodes are supported and maintained in proper position to theanode and the grids by a structure which includes a pair of insulatingblocks or discs 3| and 32 fitted within the metallic cylinder I8. Theblocks or discs'3l and 32 are mounted on and spaced by a pair ofmetallicrods 88 supported by rigid leading-in conductors 34 sealed in thevitreous member 25, the blocks or discs being locked to the rods 33 asby metallic stubs 35 embedded in the blocks or discs and affixed to therods. Mounted upon the rods 33 at the inner ends thereof are metallicstrips or bands 36 which extend through oversized apertures 81 in thecylindrical member I8 -and are aiiixed to the cathodes 38 at one endthereof.

The cathodes 88 are supported at the other end by a rigid cross-arm orrocker member 38 which is pivotally mounted upon a4 pin 38 extendingthrough and between a pair of rigid supports or uprights 48.` Thesupports or uprights 48 extend slidably through metallic bushings orbearings 4I in the blocks or discs 3i and 32 and are ernbedded at thelower end thereof in an insulating carrier or platform 42 to which theymay be locked by metallic stubs or `wires 43. The carrier or platform 42is supported by a helical spring 44 which is fitted at one end about areduced hub 45 on the carrieror platform and is seated at the other endupon an insulating block 48 having a reduced portion 41 tted within thespring 44. In the fabrication of the device, the spring 44 is placedunder compression so that it exerts an upward -force upon the carrier orplatform 42, the force being transmitted to the cathodes 88 through therods or uprights 48 and rocker member 38 so that the cathodes aremaintained under tension during operation of the device.

'cal portion 58.

As will be apparent, the control grid and cathode structures constitutea unitary assembly which may be inserted into the anode as a unit andlikewise removed as a unit to allow repair or replacement thereof.

In the embodiment of this invention illustrated in Fig. 2, the cathodes38 are supported upon the metallic cylinder I8 of the controlgrid'structure. As shown in this figure, the grids 22 are mounted uponindividual fins or plates 48 suitably afiixed, as by welding, to theouter surface of the cylinder I8. The cylinder I8 is provided with aninternal annular flange 49 having sealed thereto a metallic disc 58 uponwhich the insulating block 46 is seated, the disc 58 being provided witha central recess for receiving a reduced portion I of the block. 'I'heplatform 42 carried by the spring 44 is slidably fitted in the cylinderI8 and mounts the rods or uprights 48 supporting the rocker member 38.

The'leading-in conductors 52 for the cathodes 38, provided withinsulating sleeves 53, extend through metallic eyelets 54 projectingfrom the,

cylinder I8, and are sealed thereto hermetically by vitreous beads 55.

The flared portion 21 of the'tuning cylinder, the discs 28 and 58 andthe cylinder I8 constitute walls of the enclosing vessel and providerelatively large heat radiating surfaces so that the heat developed inthe control electrode structure during operation of the device will bedissipated rapidly and the grids 22 thereby maintained at a relativelylow temperature. If desired, a cooling medium, such as a stream of air,may be circulated through the chamber formed by the members 21., 28, 58and I8.

In a modification of the structure shown in Fig. 2, the vitreous portionI8 of the enclosing vessel may have sealed thereto a metallic memberwhich, as illustrated in Fig. 3, includes a base portion 56 having aflange 51 sealed to the vitreous portion I8, and an inwardly extendingcylindrical portion 58. 'I'he cylinder I8 of the control grid structureis frictionally fitted about the cylindrical portion 58 and the disc 28engages and rests upon the base 58. 'I'he inner end of the cylindricalportion 58 may be sealed by a vitreous member 58 fused to an inwardlyextending annular ila'nge 68 integral with the cylindri- Embedded in andextending through the'vitreous member 58 are the cathode leading-inconductors 52 which extend through apertures 6I in the cylinder i8 andare secured to the lower ends of the cathodes 38.

As shown in Fig. 4, the cylindrical portion 58 may have, alternatively,an upstanding, knifeedged annular projection 62 to which the vitreousmember 58 is hermetically sealed.

Although specific embodiments of the invention have been shown anddescribed, it will be understood of course, that various modificationsmay be made therein without departing from the scope and spirit of thisinvention as dened in the appended claims.

What is claimed is:

1. An electron discharge device comprising an enclosing vessel, acathode, an anode, a control electrode, a metallic member connected tosaid including a grid in cooperative relation with said cathode and saidanode, a hollow member supporting said grid and a cylindrical memberintegral with said hollow member, having a portion in juxtaposition tosaid anode and forming a condenser therewith, and an enclosing vesselportions of which are constituted by said hollow member and anotherportion of saidcylindrical member.

3. An electron discharge device comprising an enclosing vessel having adished portion and a cylindrical metallic wall at one end of said dishedportion, a metallic disc within the' confines of said wall and joinedthereto, a cylindrical metallic member extending into said disc andsealed thereto,l said member having an exposed heat radiating portion,andan electrode mounted on said cylindrical member. i

4. An electron discharge device comprising an enclosing vessel having avitreous portion, a metallic cylinder within and sealed to said vitreousportion, an annular disc member intermediate the ends of said cylinderand sealed thereto, a hollow member extending through said disc member,and an electrode mounted on said hollow member, said hollow and discmembers and portions of said cylindrical member constituting walls ofsaid enclosing vessel.

5. An electron discharge device comprising an enclosing vessel includinga cylindrical metallic member at one end thereof one surface of whichconstitutes an external wall of said vessel, and an electrode structuremounted on said metallic member comprising a metallic sleeve iltted tothe other surface of said metallic member and an electrode carried bysaid sleeve.

6. An electron discharge device comprising an enclosing vessel having ametallic wall adjacent one end thereof, a metallic annulus carried bysaid metallic wall, a metallic cylinder mounted on said annulus andhaving an open end in communication with the aperture therein, a gridelectrode supported by said cylinder, a disc within said cylinder andsealed thereto intermediate the ends thereof. a cathode in cooperativerelation with said grid electrode, and means mounted on said discsupporting said cathode.

7. An electron discharge device comprising an enclosing vessel having adished metallic portion and a vitreous portion, an anode element mountedon said metallic portion and having a cylindrical portion, a metalliccylinder within said cylindrical portion and sealed to said vitreousportion, said cylinder having a part constituting a wall of saidenclosing vessel, a metallic disc within and sealed to said cylinder, ametallic sleeve ailixed to said disc, a grid carried by said sleeve, acathode, and means supporting said cathode supported by said sleeve.

8. An electron discharge device in accordance with claim 7 wherein saidsleeve has a heat radiating portion extending outwardly from said disc.

9. An electron discharge device comprising an enclosing vessel includinga cup-shaped metallic portion and a vitreous portion, aninwardlyextending metallic cylinder sealed to said vitreous portion, an anodeelement having a cylindrical portion encompassing said cylinder andhaving also an annular portion, a hollow member supportedby saidcylinder, a pair of grids moimted on said hollow member, a pair ofcathodes each in cooperative relation to one of said grids, leading-inconductors extending through said hollow member and connected to saidcathodes at one end thereof, and supporting means mounted on `saidhollow member and engaging said cathod at the other end thereof.

10. An electron discharge device in accordance with claim 9 wherein saidsupporting meam comprises a platform slidably molmted within said hollowmember, a rocker member carried by said platform and having its endsaihxed to said other end of said cathodes, and a helical spring sup-`ported by said hollow member and supporting said 40 platform.

ARTHUR L. SAMUEL.

